This invention relates to the field of electronic musical instruments and, more particularly, to a method and apparatus for providing musical accompaniment at a plurality of different tempos and in different musical styles upon selection of one of the styles.
It has long been recognized in the musical performance industry that the proper selection of tempo can make or break a performance. It is therefore a major responsibility of a conductor or band leader to set the tempo for a performance. Proper tempo selection involves a great many considerations, such as, phrasing, orchestral treatment, rhythmic content and even the subjective intent of the composer. It is therefore often very difficult for an individual to select an appropriate tempo for a composition.
Electronic musical instruments have in the past incorporated tempo dependent features to promote ease of playing. Such features range from purely percussive accompaniment to full orchestral accompaniments. Regulation of the tempo at which an accompaniment is played has been achieved by generating a clock signal which is a multiple of the tempo beat rate. It has been the responsibility of the player to set the clock of the instrument so that the accompaniment is played at an appropriate rate. The rate may change significantly from one composition to another, for example, between a slow funeral dirge and a simple minuet. An instrument capable of performing a wide variety of music must therefore have a wide range of tempos available to choose from. The size of the range compounds the problem of tempo selection, making it difficult for performers with little experience or a poor sense of tempo to choose a musically correct tempo.
Attempts have been made to aid players of electronic musical instruments in the selection of an appropriate tempo. For example, the Kinsman organ, later manufactured by Seeburg, automatically adjusted the tempo to follow proportionally the rate at which the bass pedals were played. This allowed the player to dynamically alter the tempo of the accompaniment. It operated satisfactorily if the player had a good sense of tempo and played the bass pedals at a constant rate; however, it became unstable if the performer played either behind or ahead of the beat. If he played behind the beat, the tempo rate of the accompaniment would slow tremendously, causing the music to sound very badly.
Another prior accompaniment system altered the tempo clock rate when a style was changed in order to accommodate different sample rates of musical parameters within the system. Sample rates of 3 per beat were used for styles containing triplets and sample rates of 4 per beat were used for styles containing sixteenth notes. This meant that to play back accompaniments at the same beat rate, which was intended in the system, the clock rate was altered from three times the beat rate to four times the beat rate upon changing from a style containing triplets to one containing sixteenth notes. Any variation in playback rate was accomplished independently by the performer to accommodate the composition being played.
In addition, drum machines and music synthesizers have permitted musical compositions to be recorded by a player at different tempos and later sounded at those tempos in much the same manner as a tape recorder. The rate of playback has been variable by the player and, in at least one case, the change from the tempo of the original recording has been automatically reset to zero upon selection of a different track or composition. Two machines of this type are a drum machine manufactured by Oberheim as Model DMX and a sequencer manufactured by Oberheim as Model DSX for use with a compatible synthesizer. However, these machines simply replay the sequence inputted by the performer and do not react dynamically to the playing of an instrument to choose a suitable accompaniment, in the manner of many musical instruments having automatic accompaniment features. They are purely passive in this regard.
Therefore, it is desirable in many applications to provide a simple and effective system for assisting the performer of an electronic musical instrument in choosing an appropriate tempo.